Inputs
Choose a mode, then enter your measurements.
Example Data Table
Sample entries to help you verify inputs.
| Scenario | Volume | Current (ppm) | Target (ppm) | Mode | Typical action |
|---|---|---|---|---|---|
| Ornamental pond, full sun | 4,000 gal | 20 | 40 | Raise | Add stabilizer in measured doses |
| Tank with high buildup | 12,000 L | 90 | 50 | Lower | Replace a portion of water |
| Tablet-fed water feature | 2,500 gal | 30 | 30 | Tablets | Estimate future increase from product |
Formula Used
How the calculator converts ppm into mass or dilution.
Raise CYA (stabilizer)
ppm is mg/L. Convert volume to liters, then:
grams CYA = Δppm × liters ÷ 1000.
product grams = grams CYA ÷ (purity/100).
grams CYA = Δppm × liters ÷ 1000.
product grams = grams CYA ÷ (purity/100).
Lower CYA (replacement)
Dilution assumes the replacement water has 0 ppm CYA.
fraction to replace = 1 − (target ÷ current).
volume to replace = fraction × total volume.
fraction to replace = 1 − (target ÷ current).
volume to replace = fraction × total volume.
CYA from tablets
Uses common approximations:
Trichlor: ~0.6 lb CYA per 1 lb product.
Dichlor: ~0.5 lb CYA per 1 lb product.
ppm increase = (CYA mass in grams × 1000) ÷ liters.
Trichlor: ~0.6 lb CYA per 1 lb product.
Dichlor: ~0.5 lb CYA per 1 lb product.
ppm increase = (CYA mass in grams × 1000) ÷ liters.
How to Use This Calculator
A practical workflow for gardens and water features.
- Test current CYA with a fresh kit and record it.
- Measure total volume of the pond, tank, or reservoir.
- Select a mode: raise, lower, or estimate from tablets.
- Enter a target suited to sun exposure and maintenance.
- Apply results in smaller steps, then retest and adjust.
Safety reminder
Never mix products dry. Add chemicals to water, not the reverse. Keep children and pets away until the area is secure and tools are rinsed.
FAQ
Common questions for practical use.
1) What does cyanuric acid do in outdoor water?
It helps protect chlorine from sunlight breakdown. In bright conditions, this can reduce how often you need to add sanitizer and improves stability in exposed water features.
2) Why is very high CYA a problem?
Excessive CYA can reduce chlorine effectiveness, making control harder. If levels climb, dilution is usually the practical correction because CYA does not evaporate out of the water.
3) Can I lower CYA using chemicals?
Most setups rely on partial drain-and-refill or water replacement. Some niche treatments exist, but availability and results vary, so water replacement remains the dependable approach.
4) How accurate is the tablet estimate mode?
It is a planning estimate based on typical CYA yield rates. Labels and formulations vary, so treat the result as directional and confirm with testing after the product has dissolved fully.
5) What target should I choose for a garden pond?
Targets depend on sun exposure and how you sanitize. Many outdoor systems aim for moderate stabilization rather than extremes. Pick a conservative target, then adjust based on testing trends.
6) When should I retest after adding stabilizer?
Allow circulation and dissolution time. Retest after 24–48 hours, longer if water is cool. Record results, then fine-tune with smaller additions instead of one large correction.